1. Field of the Invention
The present invention relates to an adjustable armrest assembly. More particularly, the present invention relates to an adjustable armrest assembly for a chair.
2. Description of the Related Art
An office chair generally comprises two armrests that can be adjusted to a desired level relative to the chair seat. A typical adjustable armrest assembly comprises a substantially L-shaped fixed support and a sleeve mounted around a vertical section of the fixed support. An armrest is mounted on top of the sleeve, and an adjusting member can be operated to allow the sleeve to move along a vertical direction to a desired level. The adjusting member is then released and the armrest is retained in the desired level. Such a structure is disclosed in Taiwan Utility Model Publication Nos. 361169 and M263848. However, it is difficult to control the magnitude of force and speed for lifting or lowering the armrest. In other words, the adjusting operation is not smooth. Further, the armrest can not be moved to the desired level when the upward force applied to the armrest is insufficient.
Taiwan Utility Model Publication No. 582242 discloses an adjustable armrest assembly using a pneumatic rod to move the armrest upward for subsequent manual adjustment to the desired level. However, the cost is high and the pneumatic rod can not be readily used with other currently available armrest devices. Namely, troublesome modification of the currently available armrest devices is required for incorporating the pneumatic rod.